Abstract: An optical receptacle includes a first optical surface, a second optical surface, and an attenuation portion. The attenuation portion includes a plurality of first reflection parts and a plurality of second reflection parts. The plurality of first reflection parts reflects a portion of light incident on the first optical surface toward the second optical surface. The second reflection parts reflect the other portion of light incident on the first optical surface in directions other than the direction toward the second optical surface. The first reflection parts and the second reflection parts are alternately disposed along a direction perpendicular to the optical axis between the first optical surface and the first reflection parts and perpendicular to the optical axis between the first reflection parts and the second optical surface.

Abstract: Methods and systems for coupling a light source assembly to an optical integrated circuit are disclosed and may include a system comprising a laser source assembly having a laser, a rotator, and a mirror, where the laser source assembly is coupled to a die including an angled grating coupler and a waveguide. The system may generate an optical signal utilizing the laser, rotate the polarization of the optical signal utilizing the rotator, reflect the rotated optical signal onto the grating coupler on the die, and couple the optical signal to the waveguide, where an angle between a grating coupler axis that is parallel to the waveguide and a plane of incidence of the optical signal reflected to the angled grating coupler is non-zero. The angle between the grating coupler axis and the plane of incidence of the optical signal reflected to the angled grating coupler may be 45 degrees.

Abstract: An objective lens for optical pickup and an optical pickup apparatus having the same are provided. The objective lens for optical pickup includes a light source side lens surface and a disc side lens surface. The light source side lens surface and the disc side lens surface each include an effective region disposed at a central region of the objective lens and a non-effective region disposed outside the effective region. An optical path changing element, disposed in the non-effective region of at least one of the light source side lens surface and the disc side lens surface, changes a path of light incident thereon.

Abstract: An objective lens for an optical pickup device is characterized in that compatibility of three types of optical discs, which are a BD, a DVD, and a CD, may be realized by a common objective lens, and a flare can be created by providing an over-spherical aberration when a third optical disc is used from a size relationship between a pitch on a central region side and a pitch on an intermediate region side across a boundary and a relationship of a direction of a step in the base structures superimposed in a central region and an intermediate region of the objective lens.

Abstract: A system and method for providing direct read after write functionality in an optical data storage device include an optical head having a first coherent light source modulated at higher power during writing of data to the optical medium and a second coherent light source operating in a continuous wave mode at lower power while the first coherent light source is writing data. Optic components combine light from the first and second light sources and focus light from the first coherent light source to a first spot of a selected track on the optical medium and focus light from the second coherent light source to a second spot on the selected track downstream from the first spot relative to movement direction of the optical medium to read and verify the data directly after writing during the write process rather than in a separate verification process.

Abstract: Provided is an optical pickup device capable of ensuring the compatibility among three types of optical discs, i.e., BDs, DVDs, and CDs, with a common objective lens and, in addition, capable of ensuring a sufficient working distance for CDs, and also provided are an optical information recording and reproducing device and an objective lens suitable for the optical information recording and reproducing device. On the objective lens, there is arranged a first optical path difference providing structure formed such that: the direction of step differences of a basic structure wherein the diffraction order of a blue-violet laser light flux become an odd order faces toward the opposite direction of the optical axis; the direction of step differences of a basic structure wherein the diffraction order of the blue-violet laser light flux become an even order faces toward the optical axis; and both the basic structures are overlapped together.

Abstract: In the invention, a movable lens varying the rate of convergence or divergence of light reaching an objective lens by moving in an optical axis direction has its position adjusted to correspond to ambient temperature. The objective lens is arranged to be tilted with respect to an optical axis of light reaching the objective lens from the movable lens. First coma aberration of which the amount produced varies according to movement of the movable lens, and second coma aberration of which the amount produced varies due to variation in the warping state of an optical disc that is caused along with variation in ambient temperature both occur in the radius direction of the optical disc, and the objective lens has its tilting direction adjusted such that the first coma aberration and the second coma aberration have their increasing and decreasing directions of the amount of coma aberration produced with respect to variation in ambient temperature reversed.

Abstract: A disclosed optical pickup includes an aberration correction unit with a phase shifter surface. On the phase shifter surface, rectangular or staircase-like steps are formed in a concentric manner around an optical axial center, in certain regions where a light beam passes through. The steps have different heights in the optical axial direction. A light beam having a wavelength of 405 nm is directly transmitted through the steps so that a phase difference is applied for correcting spherical aberration that occurs on a first optical recording medium. A light beam that passes through an annular region without any steps is focused on a second optical recording medium. A light beam that passes through an outside region is focused by an object lens on the second optical recording medium, and is not focused on the first optical recording medium.

Abstract: A compatible near field optical recording/reproducing apparatus includes a solid immersion lens unit including a first lens, which has an aspherical surface in which light incident from the first light source is condensed, and a second lens, which realizes a high numerical aperture via a near field effect by light condensed by the first lens and has an aspherical surface. An effective beam size-controlling device controls an effective size of a light beam transmitted to the solid immersion lens unit such that either near field light or far field light is transmitted to an information storage medium by the solid immersion lens unit and a focal point adjusting optical system adjusts a focal position of light transmitted to the information storage medium according to the type of the information storage medium.

Abstract: An optical pickup includes: a first emission unit emitting an optical beam with a first wavelength corresponding to a first optical disc; a second emission unit emitting an optical beam with a second wavelength, which is longer than the first wavelength, corresponding to a second optical disc different from the first optical disc; a third emission unit emitting an optical beam with a third wavelength, which is longer than the second wavelength, corresponding to a third optical disc different from the first and second optical discs; a condensing optical device condensing, on a signal recording surface of a corresponding optical disc, the optical beams emitted from the first to third emission units; and a diffraction unit provided in the condensing optical device, which is disposed on the optical path of the optical beams with the first to third wavelengths.

Abstract: An optical pickup device that can reduce interlayer crosstalk, without changing the configuration of the optical system, and without excessively increasing the size of the optical system. The optical pickup device reproduces a signal from a multilayered optical information recording medium having a plurality of information recording layers. The optical pickup device uses a collimating lens unit as a collimating optical system that collimates light from a light source, and the collimating lens unit includes a first and second lens group arranged at a predetermined distance from each other so as to form a converged light spot in the interior of the collimating lens unit, and an optical element provided between the first lens group and the second lens group so as to form a light spot at a position defocused from the position of the converged light spot, thereby decreasing quantity of light passing through the collimating lens unit.

Abstract: An optical pickup apparatus includes: a first light source; a second light source; a light-converging optical system including a coupling lens and an objective lens; and a photodetector. The optical pickup apparatus is capable of recording and/or reproducing information by converging a light flux from each of the first and second light sources with the light-converging optical system on an information recording surface of each of first and second optical information recording media through a protective layer, and by detecting the light flux reflected from the information recording surface and passing through the light-converging optical system again, on the photodetector. The optical pickup apparatus satisfies predetermined conditions according to an optical path length from each of first and second light sources and the information recording medium, a magnification of the objective lens, and a magnification of the light-converging optical system.

Abstract: In a three-wavelength-compliant optical disk apparatus, the present invention enables to shorten time required for starting the apparatus such as discrimination of an optical disk and adjustment of a beam-expander. At the time of starting the apparatus, the operation of a tray driver which pulls a loaded optical disk within the apparatus is conducted in parallel with the operation of a beam-expander driver which allows a movable lens of the beam-expander to move to a predetermined position in accordance with the kind of optical disk. Further, at the time of discriminating the disk, the number of times an optical disk of a specific kind has continuously been loaded into the apparatus to date is stored in a memory, and a sequence of discriminating the kind of optical disk that is newly discriminated is switched by referring to the history information.

Abstract: An optical element includes: an element body including a resin containing a polymer having an alicyclic structure. The optical element is treated by one of heat treatment and wet-heat treatment for 15 hours or longer at a temperature lower by 10° C. to 30° C. than a glass transition temperature of the resin after being formed by injecting the resin in a mold. The optical element body has a length along an optical axis of the optical element in a range of 0.5 to 3 mm, and a length in a perpendicular direction to the optical axis in a range of 3 to 5 mm.

Abstract: The present invention provides a first light source (21) that emits light of a first wavelength, that at least either records onto or reproduces information from an information recording medium (30), a light source (22) that emits light of a second wavelength that records onto or reproduces information from an information recording medium (33), a light source (23) that emits light of a third wavelength that records onto or reproduces information from an information recording medium (23), focusing means, an optical element (28) that passes light of the first wavelength and diffracts light of the second and third wavelengths, wherein the optical element (28) is an optical element in which grooves are formed in a substrate, wherein the expression: 380 nm?(n?1)×d?420 nm is satisfied, where n is a refractive index of the substrate at a wavelength of 400 nm, and d (nm) is a depth per step of the grooves, and wherein the grooves are formed in two steps of depth d and depth 2d.

Abstract: There is provided an objective lens used for an optical information recording/reproducing device for recording information to and/or reproducing information from two types of optical discs, by selectively using one of two types of substantially collimated light beams including first and second light beams. When wavelengths of the first and second light beams are respectively represented by ?1 (nm) and ?2 (nm), ?1<?2 is satisfied. The objective lens includes a first optical element, and a second optical element made of material different from that of the first optical element. The first and second optical elements are cemented via a cementing surface. Further, the objective lens is configured to satisfy a condition: 0.006 < { ( nR ? ? 2 - nR ? ? 1 ) - ( nB ? ? 2 - nB ? ? 1 ) } × ? [ { ( k ? ? 2 r ? ? 2 3 ) + 8 × A ? ? 42 } × f ? ? 1 3 + 2.29 ] < 0.038 ? .

Abstract: The present invention provides a first light source (21) that emits light of a first wavelength, that at least either records onto or reproduces information from an information recording medium (30), a light source (22) that emits light of a second wavelength that records onto or reproduces information from an information recording medium (33), a light source (23) that emits light of a third wavelength that records onto or reproduces information from an information recording medium (23), focusing means, an optical element (28) that passes light of the first wavelength and diffracts light of the second and third wavelengths, wherein the optical element (28) is an optical element in which grooves are formed in a substrate, wherein the expression: 380nm?(n?1)×d?420nm is satisfied, where n is a refractive index of the substrate at a wavelength of 400 nm, and d (nm) is a depth per step of the grooves, and wherein the grooves are formed in two steps of depth d and depth 2d.

Abstract: An optical head device may include a twin laser light source which is integrally provided with a first laser beam emitting element and a second laser beam emitting element, a light receiving element, and an optical system including an objective lens for converging a laser beam on an optical recording medium. The optical system is provided with a detection lens structured of a toric lens. The toric lens applies an astigmatic difference caused by a toric face to the one of the return light beams, and the toric lens applies the other of the return light beams an astigmatic difference caused by a toric face and astigmatism composed of astigmatism and curvature of image field caused by passing off-axis position to coincide a focusing position of the first laser beam with that of the second laser beam.

Abstract: A resin objective lens having a numerical aperture NA?0.75. The objective lens satisfies a condition: 0?|SC|MAX/f<0.002 where f denotes a focal length at a wavelength ? and |SC|MAX denotes a maximum absolute value of an offence against a sine condition in a range larger than or equal to 0% and smaller than 90% of an effective beam radius with respect to an optical axis. The objective lens is configured such that the offence against the sine condition at a 100% point of the effective beam radius is smaller than that defined at a 90% point. At least a light source side surface of the objective lens is formed to be an aspherical surface, and the objective lens satisfies a condition: 1.40<(n?1)·(SAG1)?MAX·/NA2<1.95 where (SAG1)?MAX represents a maximum gradient of the light source side surface within an effective beam diameter.

Abstract: An optical pickup apparatus according to the present invention includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical element. The objective optical element has an optical surface including at least two areas provided with optical path difference providing structures. The objective optical element converges the first to third light fluxes each passing through the predetermined areas on the objective optical element onto respective information recording surfaces of the first to third optical disks. The first optical path difference providing structure is a ring-shaped structure which includes a plurality of ring-shaped zones including respective steps having at least two kinds of amounts selected from the predetermined expressions.

Abstract: An optical pickup apparatus according to the present invention includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical element. The objective optical element has an optical surface including at least two areas provided with optical path difference providing structures. The objective optical element converges the first to third light fluxes each passing through the predetermined areas on the objective optical element onto respective information recording surfaces of the first to third optical disks. In the optical pickup apparatus, the third light flux which has passed through an optical path difference providing structure forms a first best focus and a second best focus.

Abstract: An optical pickup apparatus according to the present invention includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical element. The objective optical element has an optical surface including at least two areas provided with optical path difference providing structures. The objective optical element converges the first to third light fluxes each passing through the predetermined areas on the objective optical element onto respective information recording surfaces of the first to third optical disks. One of the optical path difference providing structures includes a first basic structure and a second basic structure which are predetermined optical path difference providing structures and overlap with each other.

Abstract: In order to prevent a spectrum of a wavelength channel from becoming narrower, a device according to the present invention includes a light dividing section capable of dividing a wavelength spectrum in an input light beam and outputting a plurality of divided light beams, which are spatially separated and have wavelength spectrum portions different from each other, and a wavelength-to-special-position-converter capable of spatially multiplexing the wavelength spectrum portions of the plurality of divided light beams from the light dividing section.

Abstract: An optical pickup apparatus comprises: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical element. The objective optical element comprises an optical surface comprising a central area and a peripheral area. The central area comprises a first optical path difference providing structure, and the peripheral area comprises a second optical path difference providing structure. The objective optical element converges the third light flux which passes through the central area of on the third optical disk. The objective optical element converges the first and second light fluxes which pass through the peripheral area on the first optical disk. Each of the first and second optical path difference providing structures comprises a predetermined basic structure.

Abstract: An objective optical system for use in an optical pickup apparatus for converging first and second parallel light fluxes includes: a first lens group having a phase structure; and a second lens group, wherein the first lens group and the second lens group are arranged in the objective optical system in this order from a longer conjugate distance side of the objective optical system, and a wavefront aberration of the first lens group WL1?1, a wavefront aberration of the second lens group WL2?1, a magnification of the second lens group M, a wavefront aberration of the second lens group WL2?2, a wavefront aberration of the objective optical system WOBJ?2 are satisfy predescribed expressions.

Abstract: An optical pickup apparatus comprises: a first light source; a second light source; a third light source; and an objective optical element. The objective optical element comprises at least two areas comprising first and second optical path difference providing structures. A third light flux from the third light source passing the first optical path difference providing structure forms first and second best focuses. The third light flux passing the objective optical element forms a spot comprising a central spot portion; an intermediate spot portion; and a peripheral spot portion. The central spot portion is used for recording and/or reproducing information for a third optical disk, and the intermediate and peripheral spot portions are not used for recording and/or reproducing information for the third optical disk. The peripheral spot portion is formed on the third optical disk by the third light flux through the second optical path difference providing structure.

Abstract: An optical pickup device includes a light source emitting a light beam having a wavelength within a range of 390 nm to 420 nm and an optical element to perform recording and/or reproducing of information of an optical disk having a protective substrate thickness d1 mm using the first light beam from the first light source, wherein the optical element is made of a mixed material produced by dispersing particles into a resin, a sign of a refractive index change ?n2/?t of the particles owing to a temperature change is opposite to a sign of a refractive index change ?n1/?t of the resin owing to a temperature change, or an absolute value of the refractive index change ?n2/?t is smaller than an absolute value of the refractive index change ?n1/?t.

Abstract: An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: |?SA1/?U|·|?U|+|?SA2/?T|·|?T|?0.07 ?rms where ? represents a wavelength of a light source, ?SA1/?U represents a change of a spherical aberration for an object-to-image distance change ?U (|?U|?0.5 mm) and ?SA2/?T represents a change of spherical aberration for a temperature change ?T (|?T|?30° C.), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface.

Abstract: When a dual-layer disc was read, light returning from an irrelevant layer interfered with signal light, causing a focusing error signal and tracking error signal to vary. As a result, full-expected performance could not be obtained from an optical pickup. Disclosed is an optical pickup that includes a laser diode, which emits an optical beam; a diffraction device, which is placed at a position through which the optical beam passes, and separates the optical beam into at least three optical beams (zero-order light, plus first-order light, and minus first-order light); an objective lens, which condenses the optical beams passing through the diffraction device on an optical disc; and a detector, which receives light reflected from the optical disc. The diffraction device allows only a specific polarization direction component of an optical beam to pass without being diffracted, and diffracts a polarization direction component that is orthogonal to the former component.

Abstract: An objective lens for converging a light beam emitted from a first light source on a recording surface (17a) of a first optical information recording medium covered with a transparent substrate (7a) and converging a light beam emitted from a second light source on a recording surface (17b) of a second optical information recording medium covered with a transparent substrate (7b) having a thickness greater than the transparent substrate (7a). On an incident plane for the light beam, there are formed a center region (A1), an intermediate region (A2) surrounding the center region (A1), and a peripheral region (A3) surrounding the intermediate region (A2). A diffraction grating (11) is provided on the lens surface of the intermediate region (A2).

Abstract: An objective lens for an optical pickup is configured such that, when a light beam having a wavelength corresponding to the optical disc requiring the higher NA is converged on the optical disc requiring the higher NA at the higher NA, the phase of light flux passed through the peripheral area is substantially the same as that passed through the central area. When a light beam having a wavelength corresponding to the optical disc requiring the lower NA is converged on the optical disc requiring the lower NA at the lower NA, the phase of light flux passed through a first annular region included in the peripheral area is different from that passed through the central area, and the phase of light flux passed through a second annular region, which is outside the first region, is substantially the same as that passed through the central area.

Abstract: An optical element-for use in an optical pickup apparatus for converging a light flux onto an information recording plane of an optical information recording medium, is provided with an optical path difference providing section divided coaxially around an optical axis so as to form a plurality of ring-shaped zones; and a refracting section optimizing a spherical aberration of a converged light spot of a light flux which has the operating reference wavelength ?0 and is converged onto the information recording plane.

Abstract: An optical element having an optical axis, comprises an element body having the maximum first length of 4 mm or less in the optical axis direction and the second maximum length of 6 mm or less in the direction perpendicular to the optical axis direction; wherein the element body is made of a resin containing a polymer having an alicyclic structure and is treated by one of heat treatment and wet-heat treatment for 16 hours or longer at a temperature lower by 35° C. to 45° C. than the glass transition temperature of the resin after the element body has been formed by injecting the resin in a mold, where the glass transition temperature of the resin is measured by differential-scanning-calorimetry method at heating rate 10° C./min on the basis of JIS K7121.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, a holographic lens including a holographic ring to transmit the light beams incident in an inner region of the holographic ring, and to diffract a specific light beam among the light beams emitted from the laser light sources incident in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media to corresponding photodetectors.

Abstract: An objective lens for recording data to and/or reproducing data from first and second optical discs. The objective lens is provided with at least one surface including a plurality of annular zones divided by steps. The steps has functions of phase shifting a wavefront of light passing through the plurality of annular zones so that a beam spot formed at a converging point of an average wavefront of the wavefront phase shifted by the steps is used for the first and second optical discs. The plurality of annular zones of the at least one surface includes at least one annular zone structure which includes first and second annular zone groups, each of which has at least three steps for phase shifting the wavefront in a first direction, and a first return step which is a step formed at a boundary between the first and second annular zone groups. The first return step phase shifts the wavefront in a second direction opposite to the first direction.

Abstract: An optical recording and pickup head having a flat plate lens of a staircase type diffraction grating structure is compatible with a DVD and a CD-RW.

Abstract: An objective lens for scanning DVD and HD-DVD optical disks, comprising a first part and a second part, wherein said first part is shaped to comprise a first surface and an opposing second surface, said second part is shaped to comprise a third surface and an opposing fourth surface, said first surface is of a convex shape providing a main part of the lens power, said third surface is shaped to fit said first surface, and wherein said fourth surface is a generally aspherical surface, said second part being formed of synthetic resin material and said first part being formed of a material having a refractive index n1 having a value between 1.65 and 2, wherein the Abbe number V1 of the first part and the Abbe number V0 of the second part comply with the following relation (Formula I).

Abstract: A diffraction type lens in an optical pickup apparatus for recording and reproducing two or more kinds of optical recording media is constituted by a substrate having one surface formed with a zone plate exhibiting a smaller converging action with respect to a wavelength ?1 of light and a greater converging action with respect to a wavelength ?2 of light, and the other surface formed with a zone plate exhibiting a smaller converging action with respect to the wavelength ?2 of light and a greater converging action with respect to the wavelength ?1 of light. The substrate is transparent to the wavelengths ?1 and ?2 of light.

Abstract: A recording/reproducing apparatus having an optical pickup device which is efficient in light use having little spherical aberration.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, a holographic lens including a holographic ring to transmit the light beams incident in an inner region of the holographic ring, and to diffract a specific light beam among the light beams emitted from the laser light sources incident in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media to corresponding photodetectors.

Abstract: In an optical pickup device for conducting reproducing and/or recording of information in at least two kinds of optical information recording media, an optical element divides a light flux into k(k≧4) pieces of ring-shaped light flux. When reproducing or recording is conduced for a first optical information recording medium, the first light flux and the k-th light flux are converged on the first information recording surface and at least two pieces of light flux of the second light flux to the (k-1)th light flux form an apparent best image plane at a position different from the position of the best image plane formed by the first light flux and the k-th light flux. A wave front aberration of each light flux passing in a required numerical aperture for the first optical information recording medium is made approximately mi&lgr;1.

Abstract: An optical device scans record carriers with radiation of two wavelengths. The device has an objective lens with a diffractive part with a pattern of elements of stepped profile. The total of the step heights are substantially equal to multiples of height h1 with h 1 = λ 1 ( n - n 0 ) , where &lgr;1 is the first wavelength, n is the refractive index of the diffractive part, and n0 is the refractive index of an adjacent medium. The radiation of the first wavelength is transmitted through the diffractive part substantially without diffraction and the objective lens has a first focusing characteristic for the first wavelength.

Abstract: An optical pickup including: first and second light sources for generating first and second laser beams having different wavelengths corresponding to first and second media having different thicknesses, respectively; an objective lens that has diverging and converging/focusing portions, to focus the first and second laser beams from the first and second light sources onto the first and second media, respectively; a photodetector to receive the first and second laser beams that are emitted from the first and second light sources and reflected, respectively, by the first and second media; and a collimating lens arranged on the optical path between the objective lens, and the first and second light sources. The optical pickup is compatible with both existing digital versatile disks (DVDs), and high-definition (HD)-DVDs, which need a blue light source near 405 nm and an objective lens that has a numerical aperture of 0.6 or more.

Abstract: An optical apparatus can eliminate offset resulting from assembling errors and also can correct offset even in the photodetector of any optical system. An optical disk apparatus for reading information from tracks traces the track with the condensed spot of light beam depending on the tracking error signal obtained from the optical system for tracking error detection. The tracking error detecting optical system includes an optical apparatus having a photodetector for outputting, as the tracking error signal, a differential value of outputs of a plurality of light receiving sections for receiving the light beam condensed by the condenser lens. Also, an optical element is provided for relatively increasing and/or decreasing the amount of receiving light of a light receiving section depending on displacement of the optical axis of the light beam, in order to balance the light received by the light receiving sections and compensate for affect.

Abstract: An optical pickup apparatus having an irradiation optical system for condensing a light beam on a track of a recording plane and a photodetection optical system for guiding return light to a photodetector to detect a focal error includes a holographic lens provided in the optical path of the return light for outputting 0-th and ±1st order diffracted lights based on the return light; an optical element provided in front of or behind the holographic lens for providing astigmatism; photodetectors for receiving the 0-th and ±1st order diffracted lights; and servo-signal generating operation circuits connected to the photodetectors for generating a first and second focus error signals having a first and second capture ranges based on the output signal of the photodetector.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, a holographic lens including a holographic ring to transmit the light beams incident in an inner region of the holographic ring, and to diffract a specific light beam among the light beams emitted from the laser light sources incident in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media to corresponding photodetectors.